Issues and solutions to be noted in the operation and maintenance of multi rope friction hoist

1. Issues to be noted during operation and maintenance

1.1 Lifting during on-site installation

Two steel wire ropes are used, with the main hook steel wire rope passing through two adjacent manholes on the upper and lower abdomen plates, and the auxiliary hook steel wire rope Pass through two adjacent manholes on the lower abdomen; The main hook slowly lifts the workpiece, and the auxiliary hook cooperates to achieve a 90 °The secondary hook continues to rise, while the main hook falls, achieving a 180

Using two steel wire ropes, the main hook steel wire rope is threaded through a manhole in the upper web plate and passes around the main shaft,Exit through the same manhole. The auxiliary hook steel wire rope is suspended above the main shaft through the fixture hanging disc, and used for auxiliary leveling Use it. The screw holes at both ends of the spindle are only used to lift the lifting device and cannot be used to lift the lifting ring screws directly.

Two equally long steel wire ropes are used to pass through the gap between the upper and lower channel steel on both sides (crossing two points on each side) to lift the workpiece horizontally. It is not allowed to directly lift the lower channel steel.

Use two equally long steel wire ropes to wrap around the left and right end necks for lifting. To prevent squeezing the wheels during lifting, the steel wire rope should have sufficient length.

Head sheave wheel device with specifications below 4m: using two equally long steel wire ropes. The steel wire rope is used to suspend the wheel rims of the two wheels in the middle, and the two steel wire ropes are hung on the left and right sides of the channel steel at the same location. To prevent wheel deformation, a jack is needed to support and cushion between the two hanging wheels.

Two equally long steel wire ropes are used, with one rope hanging on each side. The lifting point is located at the gap between the upper and lower channel steel of the third wheel from top to bottom. It is not allowed to directly lift the lower channel steel. This lifting method strictly prohibits the use of bearing seats and end caps.

Using four equally long steel wire ropes, with two main hooks and two auxiliary hooks; The wire rope pocket is located on the inner side of the rim of the second and third wheels. The main and auxiliary hooks cooperate to flip. Threaded jacks should be used to assist in supporting the wheel rims near the lifting point to prevent deformation during lifting; During the lifting and flipping process, personnel should maintain sufficient safety distance from the workpiece to avoid injury caused by the falling of the jack.

1.2 Regularly check the tightening torque of high-strength bolts

Check once a day with a torque wrench within three days after putting it into operation;

▲ Check once a week with a torque wrench within 4 to 30 days after putting into operation

▲ Check once a month with a torque wrench within 2 to 4 months after putting into operation

▲ After that, according to the specific situation, the user unit shall formulate a regular inspection system to improve the tightening torque of commonly used high-strength bolts of the product: M24 750N. m; M30 1440N.m；M36 2500N.m。

1.3 Turning of friction pads

When the friction pad exceeds the above deviation requirements, correction and turning of the rope groove should be carried out. Turning rope groove: using the friction wheel two speed rope plate (formed by one-time clamping processing) as the tool alignment reference when turning the groove; Use a long straightedge to press against the outer circle of the two rope plates, so that the cutting tool tip just touches the straightedge. Record the scale on the scale ring (this scale is the 0 position), remove the ruler and turn the handwheel. Cutting forward, the feed amount can be directly seen from the scale ring on the handwheel. Each large grid rotation is equal to the tool feed amount of 0.2mm, and each small grid rotation is equal to the tool feed amount of 0.1mm. One rotation of the handwheel is equal to the tool feed or retreat of 2mm. The turning speed is generally (1-2) meters per second. Record the feed rate. Each rope groove of the car is based on this ruler. The turning accuracy can reach 0.1mm.

Multiple control modes, full range position control monitoring function; Can quickly locate each rope groove;Identify and display the wear of the rope groove online; High cutting precision, stable and reliable; The machining accuracy is not small.At 0.02mm, the control modes are manual and fully automatic; High speed milling cutter for active cutting, not Restricted by the direction of drum operation; All digital parameter settings, easy to operate.

1.4 Day (Guided) Wheel Pad Replacement Standard

The guide wheel pad is a consumable item, and its wear level should be regularly checked during use. When the wear reaches a depth of one diameter of the steel wire rope, or when the wear along the side reaches half the diameter of the steel wire rope, or when the remaining thickness of the pad after wear is half the diameter of the steel wire rope, the pad should be replaced in one of the three situations.

1.5 Floor standing hoist hanging rope and pulling rope

Each steel wire rope of the floor standing multi rope hoist has two rope grooves that can be used. When hanging ropes, if there are 4 ropes. The two steel ropes on the left side of the friction wheel centerline should be placed in their respective left rope grooves, and the two steel ropes on the right side of the friction wheel centerline should be placed in their respective right rope grooves, or vice versa. When pulling the rope, according to the direction of the rope, place one of the rope pulling devices on the friction wheel, slowly rotate the friction wheel, and the rope pulling device rotates together with the friction wheel. Gradually, the steel rope is pressed onto the rope pulling device, and is pulled into another rope groove along the guide plate at a certain angle to the center line of the friction wheel. After half a rotation of the friction wheel, the steel wire rope is no longer pressed onto the rope pulling device. After one rotation of the friction wheel, the rope pulling device returns to its original position. After pulling the rope, remove the rope pulling device.

1.6 Maintenance of main bearings and crown wheel bearings

Special attention should be paid to proper lubrication of the bearings during equipment use, as the quality of lubrication directly affects the service life of the bearings. Lubricating grease should be selected as lithium based grease 2 # or 3 #, which has excellent waterproof and corrosion-resistant properties. It is recommended to use 3 # for areas with high temperatures and 2 # for areas with low temperatures. When adding grease, be sure to clean it thoroughly and avoid bringing in dust and moisture. At the beginning of installation, it is advisable to fill 1/2 to 1/3 of the entire bearing and bearing seat space with lubricating grease.

During equipment operation, lubricating grease should be replenished once every quarter, with a replenishment amount of:

Lubricating grease should be completely replaced once a year. When replacing the lubricating grease, inject kerosene into the small hole on the bearing cover, slowly drive the bearing, and the old lubricating grease dissolves in the kerosene. Then open the oil drain hole at the lower part of the bearing end cover, drain the mixture of lubricating grease and kerosene, and continue using a container until all the old lubricating grease is cleaned.

1.7 Maintenance and upkeep of brake discs. Brake discs are an important component of friction wheels and directly affect the safety of elevator use. If the diameter of the friction wheel is less than 4m, the total runout of its end face should be ≤ 0.5mm; For friction wheels with a diameter of ≥ 4m, the total runout of their end faces shall be ≤ 0.7 mm; The surface roughness parameter Ra of the brake disc shall not exceed 3.2 μ m. When the above values exceed the standard, it is necessary to correct the brake disc.

1.8-Head/deflection sheave pulley wheel bearing maintenance

After the production of the steering wheel is completed and it is installed and used by the user, it usually remains for a period of time. At this time, the lubricating grease added by the manufacturer in the pipeline and bearing shell may have deteriorated, dried, adhered to the inner wall of the oil pipe and the oil groove of the bearing shell, and even formed blockage. Therefore, the lubricating pipeline and bearing shell must be cleaned before use to ensure the smooth flow of the lubricating oil circuit. When cleaning, kerosene and other cleaning agents are injected through the oil injection hole on the wheel rim. There is a 2-M33 × 2 oil outlet in the middle of the traveling wheel hub (which can also be used as an oil injection port), and after cleaning, it is plugged with a screw plug. The bearing grease adopts 1 # to 3 # lithium based grease. During daily maintenance, users can choose the appropriate brand of lubricating grease according to the local temperature in different seasons. It is recommended to lubricate each lubrication point once a day during the initial three months of equipment operation; Afterwards, it is required to add lubricating grease once a week at each lubrication point; Clean the bearing shell every 6 months to prevent oil circuit blockage.

2. Common problem handling and root cause analysis

2.1 Equipment abnormal noise

▲ Spindle device

After the production and manufacturing of the spindle device is completed, the downtime is relatively short. When it is installed and used, the spindle is running during operation

The device may produce abnormal noise. The main reason is the stress release process of the friction wheel, which is accompanied by

When used, any abnormal noise will be automatically eliminated.

Loose support rods between the two side plates of the friction wheel may also cause abnormal noise from the friction wheel. The main support pole

For the needs of manufacturing process and transportation, it can be directly removed during on-site installation.

Damage to the main bearing. Due to poor lubrication of bearings or impurities introduced when adding lubricating oil, there may be

It can cause damage to the rolling elements and retaining frames of the bearings, resulting in uneven force distribution during the operation of the hoist

There is a strange noise.

▲ Tianlun device

After the production and manufacturing of the Tianlun device is completed, the stagnation time is relatively short. During installation and use, the Tianlun device may produce abnormal noise during operation. The main reason is the stress release process, which automatically eliminates abnormal noise during use.

Poor lubrication of the traveling wheel bearing can cause severe wear of the bearing or cutting of the connecting bolts, resulting in abnormal noise; In the maintenance of the Tianlun device, it is necessary to add lubricating oil and clean it regularly according to the instructions.

Damage to the Tianlun bearing. Due to poor lubrication of bearings or impurities introduced during the filling of lubricating oil, it is possible to cause damage to the rolling elements and retainers of bearings, resulting in uneven operating forces and abnormal noise.

△ Wheel body welding open. In the production and manufacturing of the wheel body, it is difficult to achieve absolute consistency in the strength of all welds. In long-term operation, it will cause the weakest link to fatigue first, weld cracking, and abnormal noise. This situation can be inspected through magnetic particle or dye penetrant testing to determine the location for welding repair.

2.2 Cracking of the connecting plate at the joint between the drum shell and the two halves

① Focus on checking whether there are gaps at the joint surface of the two halves of the drum. If the gap is evenly distributed along the inside and outside of the cylinder shell, thin steel plates can be filled from the outside to the gap and firmly fixed; If the gap is uneven along the inside and outside of the cylinder shell, it is usually caused by the outer side being tightly pressed, resulting in a false impression of tightness. You can use a saddle stitch pin on the joint seam from the outside and securely fix it to tightly support the gap.

② The bolts between the two halves of the drum should be tightened to the required torque according to the specifications, and should not be tightened too tightly.

③ Drill crack stopping holes at both ends of the crack, with a recommended diameter of around 8;

④ Attach and weld reinforcement plates to the connecting plate, clean the cracks on the cylinder shell with carbon arc air gouging, and then weld the cylinder shell. Due to the inability to completely eliminate stress, attention should be paid to appropriate welding methods.

⑤ If the connecting plate is severely cracked, it can be replaced as a whole.

2.3 Main shaft end encoder small shaft fracture

Reason for small shaft cracking: The main shaft is not installed perpendicular to the bearing seat; The main shaft end drive shaft is not installed to Position; Deformation of the small shaft during transportation or installation, resulting in gear jamming during operation.

In this situation, the small shaft needs to be replaced, and lubricating oil should be applied to the gear during installation.

2.4 Wire rope head swing (jumping)

The main reasons are:

Due to the influence of the rope replacement process (replacing each individual rope one by one) and the performance of the steel wire rope itself, there may be differences in the length of the new rope, and the lifting rope with the same length may experience movement;

The bottom diameter of the friction pad rope groove exceeds the tolerance or the thickness of the steel wire rope friction grease application is uneven, causing different winding radii of the lifting rope. As the lifting height increases, the movement becomes more severe;

The position of the oil gun in the adjusting oil cylinder of the △ steel wire rope is not completely the same, or there is no remaining oil gun in the adjusting oil cylinder of a certain steel wire rope, resulting in the corresponding steel wire rope shifting.

Adjustment method:

If it is caused by inconsistent bottom diameters of the friction pads, the friction pads can be turned; If it is caused by adjusting the oil cylinder, a dedicated "through valve" can be made, which has an inlet pipe, multiple outlet pipes (matched with the number of steel wire ropes), and a 10mm ball valve at the pipe head. Multiple oil cylinders are simultaneously pressurized by an oil pump to ensure balanced force on the steel wire ropes.

2.5 Hoist head rope sliding

The main reasons are:

① Excessive braking force causes the braking deceleration to exceed the maximum acceleration, resulting in rope slippage;

② The lifting container is severely overloaded, causing the dynamic tension ratio of the steel wire rope to be greater than the friction wheel constant, resulting in slipping of the rope;

③ Poor quality of friction pads, low friction coefficient, and poor pressure and heat resistance; The anti friction grease applied on the surface of the steel wire rope has poor performance, greatly reducing the friction coefficient;

④ Violation of regulations, such as lowering a heavy skip too quickly and then applying emergency brakes;

⑤ Ground mounted equipment can cause icing on steel wire ropes and pulley rope grooves in winter;

⑥ The selection of steel wire rope does not match the friction pad, resulting in a decrease in friction coefficient;

⑦ The problem with the rope adjustment device is that when the oil pressure is too low, there is leakage in the oil cylinder, or there is no adjustment gap in the stroke of the oil cylinder piston rod, the rope adjustment function cannot be achieved, resulting in uneven lengths of the steel wire rope and different forces on the steel wire rope. The steel wire rope with excessive force will slide slightly with the lining pad when the cage is just starting or about to stop.

Preventive measures:

① By monitoring the sliding device of the steering wheel, the main control system operates to ensure reliable braking of the equipment;

② Reasonably choose hydraulic braking systems and try to use constant deceleration hydraulic braking systems with limited system vibration; When selecting a constant torque hydraulic station, the first stage brake oil pressure can be adjusted to 10MPa and the second stage brake oil pressure can be adjusted to 10.26MPa under high pressure; When the pressure is low, the first stage brake oil pressure can be adjusted to 3.04MPa, and the second stage brake oil pressure can be adjusted to 3.43MPa;

③ Strictly limit the tension ratio of the steel wire rope. If the tension ratio exceeds 1.5, it can be reduced by adjusting the weight

Value;

④ Using high-performance friction pads, selecting products with good friction coefficient, temperature resistance, and pressure resistance, and paying attention to

Observe the condition of the friction pad and perform turning maintenance on it;

⑤ Reasonably choose steel wire ropes, try to use high-quality galvanized steel wire ropes, and do not apply anti friction grease to the steel wires;

⑥ Improve the performance of the control system, strictly prevent overloading and illegal operations, and reduce rope accidents.

2.6 Spindle device movement

The main reasons are:

① The clearance of the main bearing of the spindle device is too large;

② Is there any looseness in the interference fit connection between the non transmission hub of the single flange structure spindle device and the spindle;

③ Are the anchor bolts of the bearing seat tightened; Especially for floor standing elevators, it is necessary to check the bearing's stop beam Is it loose.

Solution:

If the bearing clearance is too large, check whether the bearing model is suitable and adjust the clearance to the allowable range. If the non transmission side connection of the spindle device is loose, the spindle device needs to be removed and the friction wheel needs to be readjusted and installed. If the anchor bolts of the bearing seat become loose, the spindle device needs to be adjusted to the initial position (aligning the center line of the friction wheel with the lifting center line), and the anchor bolts need to be tightened to the required torque value.